This project focuses on the challenges when designing data transmissions for streaming media systems (realtime audio and video). It is motivated by the Yima continous media server project. The Yima server is based on a cluster design. Each cluster node provides an IP link into a distributed network fabric (e.g., Internet). The research focuses on the following aspects of this architecture:

Variable Bitrate (VBR) Media: Constant bitrate (CBR) encoding of media streams can result in either reduced quality of complex scenes or wasted storage space during simple scenes. VBR encoding on the other hand allocates bits where they are most needed, resulting in a more uniformly high visual or aural quality. The disadvantage of the VBR technique is that it results in bursty network traffic and uneven resource utilization when streaming media. Our techniques focuses on smoothing VBR media transmissions without a priori knowledge of the actual bitrate. Hence, our technique can be applied to (a) live streams and (b) stored streams without requiring any server side pre-processing.

Our technique called Multi-Threshold Flow Control (MTFC) utilizes multi-level buffer thresholds at the client side that trigger feedback information sent to the server. This technique can be applied to both live captured streams and stored streams without requiring any server side pre-processing. We have implemented this scheme in our continuous media server Yima and verified its operation across real world LAN and WAN connections. The results show smoother transmission schedules than any other previously proposed online technique.

Roger Zimmermann
Research Assistant Professor at the USC Computer Science Department
Email: rzimmerm@imsc.usc.edu
Phone: (213) 740-7654

Cyrus Shahabi
Assistant Professor at USC Computer Science Department
Email: cshahabi@cs.usc.edu
Phone: (213) 740-8162

Kun Fu
Research Assistant
Ph.D. Student
Email: kfu@usc.edu
Phone: (213) 740-2289

Mehrdad Jahangiri
Research Assistant
Master Student
Email: jahangir@usc.edu
Phone: (213) 740-4177

For licensing information please see USC's Office of Technology Licensing.

This research is funded in part by NSF grants EEC-9529152 (Integrated Media Systems Center, an NSF Engineering Research Center) and IIS-0082826 (ITR grant), and from MetroMedia Fiber Networks, through their AboveNet subsidiary, as an Industry Partner of IMSC. They are providing us with bandwidth at up to 100Mb/s from a co-location facility in El Segundo, CA.

A Multi-Threshold Online Smoothing Technique for Variable Rate Multimedia Streams
Roger Zimmermann, Kun Fu, Cyrus Shahabi, and Mehrdad Jahangiri.
Submitted for publication.

HERA: Heterogeneous Extension of RAID
Roger Zimmermann and Shahram Ghandeharizadeh.
Proceedings of the 2000 International Conference on Parallel and Distributed Processing Techniques and Applications (PDPTA 2000), Las Vegas, Nevada, June 26-29, 2000.

Abstract

Postscript

PDF

SCADDAR: An Efficient Randomized Technique to Reorganize Continuous Media Blocks
Ashish Goel, Cyrus Shahabi, Shu-Yuen Didi Yao, and Roger Zimmermann.
Proceedings of the 18th International Conference on Data Engineering (ICDE 2002), San Jose, California, February 26-March 1, 2002.

Abstract

Postscript

PDF

Cyrus Shahabi, Roger Zimmermann, Kun Fu and Shu-Yuen Didi Yao, Yima: A Second Generation of Continuous Media Servers, To appear in the IEEE Computer Magazine, 2002

Cyrus Shahabi, Farnoush Banaei-Kashani, Decentralized Resource Management for a Distributed Continuous Media Server, IEEE Transactions on Parallel and Distributed Systems, Vol. 13, No. 6, June 2002

Cyrus Shahabi, Shahram Ghandeharizadeh, Surajit Chaudhuri, On Scheduling Atomic and Composite Multimedia Objects , IEEE Transactions on Knowledge and Data Engineering, Vol. 14, No. 2, pages 447-455, March/April 2002 EEE Transactions on Knowledge and Data Engineering, Vol. 14, No. 2, pages 447-455, March/April 2002

Roger Zimmermann, Kun Fu, Cyrus Shahabi, Didi Yao, Hong Zhu, Yima: Design and Evaluation of a Streaming Media System for Residential Broadband Services , VLDB 2001 Workshop on Databases in Telecommunications (DBTel 2001), Rome, Italy , September 2001

More Info

Yima Project: http://idefix.usc.edu/projects.html
ITR Project: http://infolab.usc.edu/Report/nsf-itr.html
Yima video: http://infolab.usc.edu/Report/FinalDemoMPEG4.mpg
Infolab Main Site: http://infolab.usc.edu/
Scalable Server Lab: http://idefix.usc.edu/